Check linux/arch/mips/au1000/common/irq.c, in function init_IRQ(). Currently all the interrupt assignment are conditionalized per-board,
Well, only some of them, in particular the custom GPIO configurations. In the case of USB and other on-chip peripherals, these are always configured on all boards.
... I suspect many IRQ setups may be wrong.
I don't really think so. I've done several different Au1xxx boards and never touch this configuration for USB. I would like to hear the results of the message posted earlier today about the proper power up of the USB interface on this board :-)
Thanks.
-- Dan